In seismology, S waves are also known as secondary waves or shear waves. These terms highlight the fact that they are the second type of wave to arrive at seismic stations after P waves, the primary waves. S waves are characterized by their shear motion, which means they move particles perpendicular to the direction of the wave's propagation. This is in contrast to P waves, which move particles in the same direction as the wave is traveling. S waves are slower than P waves and cannot travel through liquids, such as the Earth's outer core, which is why they are not detected in areas where P waves can be. read more >>

In seismology, S-waves, secondary waves, or shear waves (sometimes called an elastic S-wave) are a type of elastic wave, and are one of the two main types of elastic body waves, so named because they move through the body of an object, unlike surface waves.read more >>